1. Field of the Invention
The present invention relates to thermal imageable toner developed media, and particularly to such media which is addressed by coherent radiation such as lasers or light emitting diodes.
2. Background of the Art
There are numerous processes where images can be formed by causing a radiation-sensitive or heat-sensitive layer to become tacky or fluid in imaged areas and then developed by the application of powder or liquid to the tacky or fluid areas. An example of such a process is disclosed in U.S. Pat. No. 3,941,596.
It has to date been conventional practice for the imaging to be performed by thermal printheads, with the imagewise applied heat being used to create latent images of tackified or fluid composition on the imageable surface. Such physically contacting thermal printheads suffer from a number of problems including significant limitations on the resolution of the image (effectively limited to the physical size of the individual printheads) and adherence of matter from the receptor sheet onto the printheads. A solution to this latter problem is suggested in U.S. Pat. No. 4,755,396 where antifouling agents are included in the receiving medium. Amongst the antifouling agents disclosed are fluorocarbon polymers.
U.S. Pat. Nos. 4,608,329 and 4,683,191 disclose improved toner powders for use with thermally imageable media which produce supercooled liquid area from solid materials during the thermal imaging process. These supercooled liquid areas absorb the toner powders more readily than the solid areas and thereby differentiate the image.
U.S. Pat. No. 4,968,578 discloses a method of non-electrostatic transfer of toner powder to a substrate having a polymeric coating layer and a release layer over the polymeric coating. Perfluorinated release agents are included amongst the disclosed release layer materials, and the image is formed before transfer to the receptor without creating differential adherent properties on the surface of the receptor.
U.S. Pat. No. 5,286,604 discloses a photothermotackifiable composition which is addressable by lasers. The composition contains an infrared absorbing dye to assure effective radiation absorption and heat conversion by the infrared laser addressing equipment. Toning systems are also disclosed for the media containing the composition.